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Biomedical subjects

T Webb

Publications and source records attributed to T Webb.

At least 91 records · Page 5Linked to original sources
PubMed1992

Angelman syndrome with a chromosomal inversion 15 inv(p11q13) accompanied by a deletion in 15q11q13.

A family is described in which an inversion of chromosome 15, 15 inv(p11q13), is segregating. All family members are healthy except the proband who is a 10 year old boy with Angelman syndrome. Although the chromosomal inversion has been passed from the grandfather to both his son and his daughter with no ill effect, passage from daughter to grandson has resulted in a deletion of chromosome 15 material which is presumed to be the cause of Angelman syndrome in this boy. The probabilities of an inversion of this type being instrumental in causing the syndrome are discussed.

Angelman Syndrome↗
PubMed1992

Expression of the fragile-X in the "premutated"/"non-imprinted" state.

Data about the expression of the fragile site at Xq27.3 from 74 daughters of normal transmitting males (NTMs) were collected from 7 different genetic centers. The majority (85.1%) of these obligate female carriers did not show any cytogenetic expression of fra-X. The remaining 14.9% of these females had frequencies below 3%. In cases with a frequency below 3% of fra-X, a "premutated"/"non imprinted" state of a female carrier should be considered. The results of this collaborative study are in accordance with data from DNA studies taking the premutation model into account.

Female↗
PubMed1992

Role of the independent duty corpsman on the USNS Comfort (T-AH 20): the Operation Desert Shield/Desert Storm experience.

Independent duty corpsmen (IDCs) have a significant role in providing health care on the USNS Comfort (T-AH 20). The IDCs are responsible for staffing sick call, emergency response teams, and resuscitation/stabilization teams. IDCs are trained in advanced patient care and in medical administrative and logistical duties. During peacetime, their function often focuses on primary care to the decrement of skills necessary to perform in medical emergencies. The Operation Desert Shield/Desert Storm mobilization has emphasized the need for Navy medicine to continue its support of IDC training so that they are kept in a state of preparedness to competently deliver the full spectrum of care that is expected of them.

Allied Health Personnel↗
PubMed1991

Uniparental paternal disomy in Angelman's syndrome.

Angelman's syndrome and Prader-Willi syndrome are both causes of mental retardation with recognisable, but quite different, clinical phenotypes. Both are associated with deletions of chromosome 15q11-13, of maternal origin in Angelman's and paternal in Prader-Willi. Prader-Willi can arise by inheritance of two chromosomes 15 from the mother and none from the father (uniparental maternal disomy). In 2 patients with Angelman's syndrome we found evidence of uniparental paternal disomy. The phenotypic effects of maternal and paternal disomy of chromosome 15 are very different and inheritance of two normal 15s from one parent does not lead to normal development--strong evidence in man for genomic imprinting, in which the same gene has different effects dependent upon its parental origin.

Alleles↗
PubMed1991

Expression of fragile-X in a female fetus diagnosed after chorionic villus sampling.

Study of different tissues of an aborted female fetus showed similar levels of fragile-X expression (6.3-9.2 per cent) and of early replication of the FRAXA-positive cells (50-66 per cent) in fetal tissues. Different culture media did not significantly affect either investigation. It is suggested that the distribution of X-inactivation in FRAXA-positive chorionic villus cells of a female fetus might indicate her future phenotype.

Cells, Cultured↗
PubMed1991

Moderate and mild mental retardation in the Martin-Bell syndrome.

A survey of children attending schools for the moderately or the mildly mentally handicapped has shown that two out of 25 boys and two out of 22 girls with idiopathic moderate mental retardation had the Martin-Bell syndrome, while none of 75 boys and one out of 51 girls with mild mental retardation were FRAXA positive. Consideration of these figures along with published studies suggests that 7% of moderate and 3.8% of mild idiopathic mental retardation in boys, and 2.5% of moderate and 3.3% of mild idiopathic mental retardation in girls may be due to the Martin-Bell syndrome.

Child↗
PubMed1991

Clinical investigation of females with the Martin-Bell syndrome and risk assessment for carrier status.

Anthropometric measurements were made on a series of females heterozygous for the fragile-X syndrome. It was found that there were no simple series of discriminating features separating those of normal IQ from the mentally handicapped, but rather that the carriers studied represented a wide spectrum of phenotype. When measurements performed on 15 FRAXA negative, obligate carriers of normal IQ were considered separately, it was found that there were certain common phenotypic features allowing risk figures to be amended for those females at 50% risk of being a carrier but who are also FRAXA negative.

Adolescent↗
PubMed1990

Folate treatment of a boy with fragile-X syndrome.

A severely behaviourally disturbed three year old boy with the fragile-X syndrome was treated with intermittent folate therapy over a period of 2 years. No behavioural improvement was noted in this time but variations between cultural regimes for the successful detection of the fragile-X marker were observed.

Child, Preschool↗
PubMed1990

Fragile Xq27.3 in female heterozygotes for the Martin-Bell syndrome.

X inactivation studies have been carried out on lymphocytes from eight unrelated females heterozygous for the Martin-Bell syndrome. Four of these carriers were of normal IQ and four were mentally handicapped. When BrdU was used to differentiate between the active and inactive X chromosome an average of 55% of fra(X) were active in the retarded subjects, but only 27% were active in those of normal IQ. When 3H thymidine was used to differentiate between the active and inactive X chromosome, an average of 58% of mitoses from handicapped subjects and 33% of mitoses from normal subjects showed an active fra(X) in informative cells. These results are compared with previously published studies and it is concluded that the number of inactive fra(X) chromosomes calculated as a proportion of all cells scored is the same in mentally normal and mentally retarded subjects. However, the number of active fra(X) chromosomes is consistently higher in the retarded than in the normal females.

Bromodeoxyuridine↗
PubMed1989

Autoradiographic localization of [3H] gamma-aminobutyric acid in neuronal elements of the rat gastric antrum and intestine.

High-affinity uptake and localization of radiolabelled gamma-aminobutyric acid (GABA) has been examined using light microscopic autoradiography in laminar preparations and transverse paraffin sections of the rat stomach, and small and large intestine. In the presence of beta-alanine (10(-3) M), a substrate specific inhibitor of high-affinity GABA transport into glia, tritiated GABA was accumulated by a high-affinity uptake system into myenteric ganglia and a subpopulation of mucosal cells. In the small and large intestine high-affinity uptake of [3H]GABA was evident in myenteric ganglion cells, extra-ganglionic sites and in the deep muscular nerve plexus of the circular muscle layer. Such labelling could be prevented in tissue treated with the specific neuronal high-affinity uptake blocker, L-2,4-diaminobutyric acid dihydrochloride (L-DABA; 10(-3) M), and therefore represented the selective distribution of [3H]GABA uptake sites to intrinsic neuronal elements of the rat gastrointestinal tract.

Acetanilides↗
PubMed1989

Food irradiation.

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Consumer Advocacy↗
PubMed1989

The inactivation of the fragile X chromosome in female carriers of the Martin Bell syndrome as studied by two different methods.

Female heterozygotes for the fragile X syndrome show variable levels of mental handicap from normal to severely retarded. The degree to which they are affected may depend upon whether the fragile or the normal X chromosome is preferentially inactivated, but one of the problems with the use of BUdR for the study of Lyonisation in fragile-X heterozygotes is that it reduces the level of expression of the fragile site. Results obtained by this method will be biased if the suppression occurs preferentially in either the active or the inactive X chromosome. To confirm that BUdR does not preferentially cause repair of the fragile site on either the late or the early replicating X chromosome, a comparison was made between the percentage of active or early fragile-X obtained using BUdR, and that obtained using tritiated thymidine in cells from the same heterozygote.

Bromodeoxyuridine↗
PubMed1987

Children with the fragile X chromosome at schools for the mildly mentally retarded.

An investigation of children in schools for the moderately mentally handicapped in Coventry demonstrated that 29 of 259 children had a significant chromosomal abnormality. 10 of 155 boys (6 per cent) and 10 of 104 girls (10 per cent) had the fragile X syndrome. The clinical features which suggested this syndrome in males were IQ in the 50 to 70 range, head circumference greater than the 50th centile and post-pubertal testicular volume greater than the 50th centile. For both males and females, large ears were a useful sign. All children with fragile X had a carrier parent. The occurrence of mental retardation among sibs was one in two for brothers and one in four sisters. Considering all the males with fragile X syndrome resident in Coventry (this and previous studies), there were twice as many in schools for the moderately mentally handicapped as there were in schools for the severely mentally handicapped. There were as many females as males in the schools for the moderately mentally handicapped.

Cephalometry↗
PubMed1987

Studies of the parathyroid hormone gene in normal subjects, and in subjects with primary hyperparathyroidism and familial benign hypercalcaemia.

Familial benign hypercalcaemia (FBH) closely resembles primary hyperparathyroidism (PHPT) both clinically and biochemically. Using a cDNA probe for the parathyroid hormone (PTH) gene we have studied restriction fragment length polymorphisms in normal British subjects and have shown them to be similar to those found in previous studies in a German population. The pattern of inheritance of these restriction fragment length polymorphisms in a family with FBH shows that the PTH gene is not involved in the pathogenesis of the condition. Limited studies in PHPT indicate that it is unlikely that a major structural defect or rearrangement is responsible for the sporadic form of the disease.

Alleles↗